PROTEIN REQUIREMENTS 69 



another factor of considerable importance may be mentioned, the 

 activity of the organism. 



The Work of Chittenden. 



As regards the practical protein minimum for an everyday dietary 

 there is a great difference of opinion, more particularly since the in- 

 teresting work of Chittenden was published. Voit had laid it down as 

 the result of repeated experiment and observation that the daily in- 

 take of protein should be about 120 grms. Chittenden (93) believes 

 that this amount is much too abundant, and that any person who 

 lives up to this standard and who encourages others to do so is en- 

 couraging individual and race suicide. 



He was able to maintain nitrogen equilibrium on diets which con- 

 tained about 6 grms. of nitrogen, equivalent to some 40 grms. of pro- 

 tein, and which were in addition of very low caloric value, 27 to 28 

 calories per kilogram. Chittenden's investigations were not merely 

 confined to experiments on himself, but were arranged on a large scale 

 and carried out on three different classes of men : (l) professional men 

 engaged for the most part in laboratory work, (2) on student athletes 

 who were in training for various university contests, and (3) on soldiers 

 who performed a series of regulated exercises daily. The period 

 during which these men were under investigation was also a prolonged 

 one, thus giving the experiment a good chance of failure. Chitten- 

 den maintained that the results were excellent both physically and 

 mentally in all classes of individuals on an intake of protein on the 

 average about half that of the so-called Voit standard. 



As a matter of fact the intake of protein in the diet of the average 

 individual, as evidenced at least by the output of nitrogen in the urine 

 is not so large as is commonly believed. It has become a habit to 

 assert that the average intake of protein in the food of the average 

 man is large, but this assertion is probably not true, particularly in 

 the case of those who follow sedentary occupations. Thus Hamill 

 and Schryver (168), for example, examined the urine of seven indi- 

 viduals in the Physiological Laboratory of University College, London, 

 who, during the period of examination, maintained their everyday 

 existence, no care being exercised in the choice of food, and they found 

 that the output of nitrogen corresponded to an intake of some 90 grms. 

 of protein per diem. From my own experience this amount is probably 

 a good average value. 



